The aggression paradox: Understanding links among aggression, sensation seeking, and the consideration of future consequences.

Four studies involving 573 female and 272 male college students demonstrated that multiple forms and measures of aggression were associated with high levels of sensation seeking, impulsivity, and a focus on the immediate consequences of behavior. Multiple regression analyses and structural equation models supported a theoretical model based on the general aggression model (C. A. Anderson & B. J. Bushman, 2002), positing that hostile cognition and negative affect mediate the relationships between the aforementioned individual differences and aggression. Sensation seeking also predicted a desire to engage in physical and verbal aggression. The final study demonstrated that relative to those scoring low, individuals scoring high on the consideration of future consequences are only less aggressive when aggression is likely to carry future costs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sexual orientation-related differences in prepulse inhibition of the human startle response.

Prepulse inhibition (PPI) refers to a reduction in the startle response to a strong sensory stimulus when this stimulus is preceded by a weaker stimulus--the prepulse. PPI reflects a nonlearned sensorimotor gating mechanism and also shows a robust gender difference, with women exhibiting lower PPI than men. The present study examined the eyeblink startle responses to acoustic stimuli of 59 healthy heterosexual and homosexual men and women. Homosexual women showed significantly masculinized PPI compared with heterosexual women, whereas no difference was observed in PPI between homosexual and heterosexual men. These data provide the first evidence for within-gender differences in basic sensorimotor gating mechanisms and implicate the known neural substrates of PPI in human sexual orientation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sensor technologies for monitoring metabolic activity in single cells-part I: optical methods

A review of optical, chemical, and biological sensors to detect metabolic activity at the single-cell level is presented in the context of the development of lab-on-a-chip research instrumentation. The sensors reviewed include optical sensors, at both research and commercial levels, that can optically detect intracellular metabolites including adenosine triphosphate, nicotinamide-adenine dinucleotide, reduced flavin adenine dinucleotide, and other metabolites, including oxygen, carbon dioxide, and glucose. Methods to optically detect pH changes which are a general indicator of activity in extracellular space are also briefly reviewed. Performance metrics such as sensitivity, sensor size, drift, time response, and sensing range are included when available. Highly suitable optical sensor technologies for monitoring cellular metabolic activity include luminescent (fluorescent, phosphorescent, and chemiluminescent) and colorimetric optical probes. Different approaches to extracting luminescent and colorimetric information are reviewed, including benchtop techniques, fiber-optic approaches, and the use of probes encapsulated by biologically localized embedding. A brief discussion of alternate optical sensor technologies, such as surface plasmon resonance and infrared absorption spectroscopy, is also presented.     

The negated conditional: A litmus test for the suppositional conditional?

Under the suppositional account of conditionals, when people think about a conditional assertion, "if p then q," they engage in a mental simulation in which they imagine p holds and evaluate the probability that q holds under this supposition. One implication of this account is that belief in a conditional equates to conditional probability [P(q/p)]. In this paper, the authors examine a further implication of this analysis with respect to the wide-scope negation of conditional assertions, "it is not the case that if p then q." Under the suppositional account, nothing categorically follows from the negation of a conditional, other than a second conditional, "if p then not-q." In contrast, according to the mental model theory, a negated conditional is consistent only with the determinate state of affairs, p and not-q. In 4 experiments, the authors compare the contrasting predictions that arise from each of these accounts. The findings are consistent with the suppositional theory but are incongruent with the mental model theory of conditionals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Tale of Two Cities: Financing Two Voucher Programs for Substance Abusers Through Community Donations.

Voucher-based reinforcement therapy (VBRT) is an effective drug abuse treatment, but the cost of VBRT rewards has limited its dissemination. Obtaining VBRT incentives through donations may be one way to overcome this barrier. Two direct mail campaigns solicited donations for use in VBRT for pregnant, postpartum, and parenting drug users in Toronto, Ontario, Canada, and in Los Angeles, California. In Toronto, 19% of those contacted over 2 months donated $8,000 ($4,000/month) of goods and services. In Los Angeles, nearly 26% of those contacted over 34 months donated $161,000 ($4,472/month) of goods and services. Maintaining voucher programs by soliciting donations is feasible and sustainable. The methods in this article can serve as a guide for successful donation solicitation campaigns. Donations offer an alternative for obtaining VBRT rewards for substance abuse treatment and may increase its dissemination. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Experimental realization of a new transistor

The authors report on the fabrication and characteristics of a unipolar, three-terminal, resonant-tunneling transistor. The operating principle of this new transistor is based on the fact that the quantum mechanical resonant-tunneling probability of hot electrons between the emitter and the collector is switched almost completely on and off, when either the base or the collector bias is swept. The emitter injects hot electrons to the second lowest subband of a thin (100 Å in this work) GaAs quantum well. Subsequently, the hot electrons will either resonantly tunnel to the collector, or relax to the lowest subband and contribute to the base current. As a result of resonant transmission, at 77 K the current-voltage characteristics of the transistor display negative differential resistance with extremely large (4691) peak-to-valley ratio. Furthermore, when biased near resonance, a maximum DC current gain of ~1.2 and a maximum AC current gain of ~11.9 were observed. The first use of a new `tunneling-in and tunneling-out' scheme in contacting a thin quantum well is also demonstrated     

A branch and cut algorithm for the VRP with satellite facilities

An important aspect of the vehicle routing problem (VRP) that has been largely overlooked is the use of satellite facilities to replenish vehicles during a route. When possible, satellite replenishment allows the drivers to continue making deliveries until the close of their shift without necessarily returning to the central depot. This situation arises primarily in the distribution of fuels and certain retail items. When demand is random, optimizing customer routes a priori may result in significant additional costs for a particular realization of demand. Satellite facilities are one way of safeguarding against unexpected demand. This paper presents a branch and cut methodology for solving the VRP with satellite facilities subject to capacity and route time constraints. We begin with a mixed-integer linear programming formulation and then describe a series of valid inequalities that can be used to cut off solutions to the linear programming relaxation. Several separation heuristics are then outlined that are used to generate the cuts. Embedded in the methodology is a VRP heuristic for finding good feasible solutions at each stage of the computations. Results are presented for a set of problems derived from our experience with a leading propane distributor.     

Generic Representation of Solid-Object Geometry for Genetic Search

Abstract: This paper examines the first stage of using genetic algorithms in design—how to encode designs as chromosomes. Generic representations capable of describing the geometry of any solid object to eliminate the unnecessary duplication of work at this stage are explored. A suitable low-parameter, spatial-partitioning representation is then proposed, using partitions consisting of six-sided polyhedra intersected by planes. Finally, the coding of the representation is examined, with the conclusion that allelic coding with control genes and user-definable, fixed-value alleles would provide the most flexible system.     

Geometric model for nuclear absorption from microscopic theory

A parameter-free geometric model for nuclear absorption is derived from microscopic theory. The expression for the absorption cross section in the eikonal approximation taken in integral form is separated into a geometric contribution, described by an energy-dependent effective radius, and two surface terms which are shown to cancel in an asymptotic series expansion. For collisions of light nuclei, an expression for the effective radius is derived using harmonic-oscillator nuclear density functions. A direct extension to heavy nuclei with Woods-Saxon densities is made by identifying the equivalent half density radius for the harmonic-oscillator functions. Coulomb corrections are incorporated and a simplified geometric form of the Bradt-Peters type obtained. Results spanning the energy range of 1 MeV/nucleon to 1 GeV/nucleon are presented. Good agreement with experimental results are obtained.     

Phase equilibria in InAsSbP quaternary alloys grown by liquid phase epitaxy

The quaternary alloy InAs_1−x−ySb_xP_y, lattice-matched to InAs, is a promising material for the production of infrared light sources for the detection of gases in the 2–4 μm region of the spectrum. In this work, thermodynamic phase equilibrium calculations have been carried out to determine the compositions required for liquid phase epitaxial growth and the extent of the miscibility gap in the solid material. For high band gap materials, the desired growth temperature is found to be intermediate between a low temperature required to grow P-rich solids and higher temperatures required to avoidspinodal decomposition. Conventional LPE growth at an intermediate temperature of 583°C is found to produce good material with high luminescence efficiency and excellent optical characteristics. Problems with phosphorus loss from the melt are also discussed and lower growth temperatures are found to considerably reduce this problem. Growth in the metastable region between the binodal and spinodal lines has been achieved with the production of phosphorus-rich solids with concentrations up to y = 0.445.